Coding and decoding apparatus



March 16, 1937. w s, LEMMQN 2,074,058

CODING AND DECODING APPARATUS Filed June 16, 1954 3 Sheets-Sheet 1 SPACE 5M 2 IN VEN TOR.

I'm/fer 6. Lemma/v.

A TTORNEYS.

' March 16,1937. w, LEMMN 2,074,058

CODING AND DECODING APPARATUS March 16, 1937. w. s. LEMMON 2,074,058

comm AND nmcomuc APPARATUS Filed June-l6, 1934 3 Sheets-Sheet 3 Walter S. Lemman A TTORNEYS.

Patented Mar. 16, 1937 CODING AND DECODING APPARATUS Walter S. Lemmon, New York, N. Y., assignor, by mesne assignments, to International Business Machines Corporation, New York, N. Y., a corporation of New York Application June 16,1934, Serial No. 130,905

21 Claims.

This invention relates to apparatus for coding and decoding communications, and has for an object to provide for the rapid and accurate coding and decoding of such communications with a minimum of labor and with no demand upon the operator for a knowledge of cryptography.

It is an object of the invention to provide an apparatus which will automatically code a message as a result of the mere typing of the uncoded message, and which will automatically decode the message as a result of the mere typing of the coded message.

It is a further object of the invention to provide means for changing the code at will. It is a feature that the code can be changed instantaneously so that by prearrangement or otherwise the code may be changed several times in the transmission of a single message, if desired.

The illustrative embodiment of the invention ineludes the following desirable features. The apparatus comprises two typewriters adapted to be interconnected for coding purposes, but also adapted to be separately operated for ordinary office use when not required for coding purposes. The apparatus is effective, when the uncoded message is typed, to produce both a correct writing of the copy and a writing of the same message in code, and, when the coded message is typed, to produce a correct writing of the code message for comparison with the copy and a correctly typed translation of the code message.

It is a further object of the invention to provide an apparatus in which the coded message is automatically divided into equal groups of letters, say five letters to a group, and in which the decoded message, upon the mere copying of the coded message, is caused automatically to appear with the words properly divided and no extra spaces or characters included.

As a part of the mechanism for producing the code message in live letter groups, it is a feaiure that provision is made of means for automatically producing a space in the secondary ma chine after every fifth keyboard operation of the primary machine. It is a further feature that the mechanism is so arranged that a printed character will always be produced in the seccndary machine by the operation of either a cha acter key or the space bar of the primary machine when coding so that no intended lett group is subdivided into two groups of a lesser number of letters than that intended.

In general, any letter or character struck on the primary machine will produce a definite code 55 or translation letter on t e seco da y ach ne,

and this relation involving the same two characters will hold whether the machines are being used for coding or decoding, the two characters being always reciprocally paired for any selected 1 code setting. An exception is made, however, with 5 reference to the space bar and the dash key, the connections to these members in both the primary and the secondary machine being difierent from the connections to the other character keys. In coding the operation of the space bar produces a particular letter, and in decoding the same letter produces a space in the translation. The same letter, however, produces a dash when coding, and is produced by a dash when decoding. Provision is made of means for instantaneously altering the operating connections between the primary and secondary machines to produce this change in the mode of operation.

It is a further feature that the connections to the keyboard members of the primary and secondary machines are connected in inverse sequence to relatively rotatable contact members. In order that this may not result, however, in too simple a code, or in a too limited variety, both machines include a switchboard arrangement whereby the sequence of letter connections to the circular contact members may be changed as desired so long as the order or sequence upon one circular member is made the exact opposite of that upon the other.

It is a further feature that the apparatus is equipped with means adapting it for operation either from a direct or alternating source of current supply.

It is a further feature that provision is made to render the code changing mechanism inoperative when desired so that there is no danger of an unauthorized person tampering with the machine and ignorantly changing the code without knowledge of the authorized, operator.

It is a further feature of the invention to provide means for indicating to the operator that a particular or zero code setting exists in order that he may have a starting basis for setting the machine to any desired code.

Other objects and advantages will hereinafter appear.

In the drawings which illustrate one embodiment of the invention, and which form a part of this specification:

Figure 1 is a diagrammatic view illustrating in part the primary and secondary machines and the operating connections between them;

Figure 2 is a view in sectional elevation, partly broken away, illustrating the commutator or coding mechanism through which the coding and decoding are accomplished;

Figure 3 is a view in end elevation of the coding rings;

Figure 4 is a fragmentary, sectional view taken on the line 4-4 of Figure 2, looking in the direction of the arrows; and

Figure 5 is a sectional view taken on the line 5-5 of Figure 2, looking in the direction of the arrows.

The coding apparatus as illustrated herein comprises a primary typewriter I and a secondary typewriter 2, both of which are desirably of the electromatic type. Each typewriter comprises a constantly rotating cylinder 3 which operates cams such as 4 and 5 to produce the actuation of the carriage feed mechanism or the type bars 6 when they are tripped by the space bar I or a character key 8. There is one of these cams for each character key and one for the space bar. The character key marked 9 is taken as the dash key in both machines for the purpose of this description. Theoperation of any character key of the primary machine will cause the associated type bar 6 to be swung to a printing position in which the type carried by it strikes against the platen l0.

Each shaft II is driven from a motor (not shown), the field windings of the motors being connected between conductors l2 and l3. The entire apparatus is operated from a suitable source of line current, either A. C. or D. C., and the motors are of the universal type. The current may be regarded as coming in through a .conductor l4, passes thence through a conductor l5 to the conductor l2. After passing through the field windings of the motors the current passes through the conductor l3 and a conductor I6, thence through a control switch l1 and a conductor l8 back to the line.

The general construction and mode of operation of the apparatus will first be described withupon the shaft 31.

out reference to the features peculiar to the space bar and the dash key, and a description of the space-dash feature will then be given. In the primary machine provision is made of a multiplicity of switches l9, each of which is normally open, but adapted to be closed by one of the cams 4 or 5. Taking one of these switches other than that of the space bar or the dash key as illustrative, it will-be observed that the closing of the switch which is produced by the actuation of the associated character key completes a circuit as follows: Current coming in through the conductor [4 passes through the conductor E5 to a conductor 20, and thence through a resistance 2| to a contact 22. A plug 23 will be inserted between resilient conductors 24 and 25 to spread them apart when the apparatus is connected to a source of D. C. current, and such a setting will be assumed until otherwise stated. The current passes from contact 22 through conductor 24 and. a conductor 26 to a terminal 21. From the terminal 21 the current passes through a conductor 28, a conductor 29, a resistance 30 and a conductor 3! to the closed switch IS. The current passes thence through a conductor 32, a plug 33, a 'conductive socket 3d and a conductor 35 to a conductive ring 36 which is fast upon, but insulated from, a shaft 31. The ring 36 is connected through a conductor 38 with a contact 39 cars .ried'by an insulating ring 40 which is also fast There is a, multiplicity 01L.-

such contacts 39, the contacts being equally spaced circumferentially completelyaround the ring. A commutator ring 4| is mounted on the shaft 31 and has an equal number of contacts which are also equally spaced. The current flows through the contact 39 to the associated contact 42 of the commutator ring, and thence through a conductor 43, a plug 44, a socket 45 and a conductor 46 to the winding 41 of an elec tromagnet mounted beneath the keyboard oi the secondary machine. The electromagnet includes a core 48 which is carried by a stem 49 suspended from one of the key levers 50 of the secondary machine. The core or armature 48 pulls the key lever 50 down to cause an actuation of the associated type bar of the secondary machine when the winding of the electromagnet is energized. The current passes from the winding of the electromagnet 41 to aconductor 5|, thence through a conductor 52, a winding 53 of an electromagnet, whose purpose will be described farther on, conductors 54, 55, 56, 51, 58, 59, 60 and I6, switch l1, and conductor [8 back to the line.

While it is not proposed to go into detail as to the dash-space arrangement for the time being, it should be noted that when coding, the dash switch of the primary machine is rendered inoperative and the space switch is efiective to produce a character in the secondary machine. Thus the spaces struck when coding appear as letters in the coded message, which letters are subsequently decoded as spaces.

It is desirable both from the standpoint of making the code diflicult to decipher and from the standpoint of saving telegraph and cable charges, to arrange the characters in five charelectromagnet winding 53. The armature iii of this electromagnet is carried by a lever 62 which is pivoted at 63 and which carries a pawl lever 64. A tension spring 65 pulls one arm of the lever 62 down against a fixed stop 56 to maintain the armature 6! normally in an elevated position.-

A tension spring 61 interposed between the tail of the pawl 64 and an ear 58 on the lever 62 urges the pawl into engagement with a ratchet wheel 69. The ratchet wheel 69 is fast upon a shaft 10 and through the shaft it drives a contact ring H The ring is illustrated as having four contacts 72 which are adapted for successive engagement with a contact 13 at appropriate points in the revolution of the ring H. The ratchet wheel is illustrated as having twenty teeth, although obviously the number of teeth of the ratchet and the number of contacts of the segment ring may be varied, depending upon the letter grouping desired and upon convenience and efliciency of design, so long as the number of ratchet teeth is a multiple of the number of ring contacts 12. At each keyboard operation of the primary machine the pawl 54 istreciprocated once and feeds the ratchet wheel one tooth-space. At each fifth feeding step one of the contacts 72 wipes momentarily across the contact 13 and closes a circuit for actuating the space bar of the secondary machine.

The connection of the positive source of line current with the terminal 21 has already been described, and the connection of the negative source of current to a terminal 5'! located in the conductor 51 has already been described, and

hence for brevity these two terminals will be taken as the terminal points of the circuit. The current passes from the terminal 21 through conductor 28, conductor 14, resistance 15, and conductors 1B and 11 to the ring 1I. It passes thence through one of the ring contacts 12, contact 13, conductor 18, switch 19, conductor 80, switch 8|, contact 82, conductor 83, conductor 84, space bar solenoid 85, and conductor 86 to the terminal 51 The result is that a space is automatically introduced after each fifth character printed by the secondary machine. The switch 19 is provided to enable the feature of automatic spacing to be eliminated, if desired, and the opening of the switch does not adversely affect any of the other operating instrumentalities. When the switch is open the solenoid 53 is still energized as before and produces a rotation of the ratchet wheel 09, but the rotation of the ratchet wheel 69 is ineffective to produce any operation.

The arrangement of the coding armature or rings is illustrated more or. less in detail in Figures 2 to 5. In Figure 3 a sequence of letters and other characters is indicated opposite the contacts of the outer ring 40, and the same series of characters in the opposite or inverse sequence is indicated upon the contacts of the inner ring 8|. The general principle of this arrangement produces the result that when a given character is struck in coding a substitute character is produced on the secondary machine and that when the substitute character is struck in decoding the original character is produced upon the secondary machine. Since the simple alphabetical sequence indicated, however, might, if invariably employed, produce codes which could be solved by experts with considerable facility, the switchboard composed of the plugs 33 and the sockets 34 is provided in connection with the primary machine for changing the sequence of characters upon the inner ring, and the switchboard composed of the plugs 44 and the sockets 45 is provided in connection with the secondary machine for enabling the sequence of character connections upon the outer ring to be correspondingly changed so that the characters will still occur in exactly opposite order on the inner and outer rings.

The shaft 31 is mounted at its opposite ends in bearings 81 which are carried by brackets 88 supported from a frame member 89. A cylindrical insulating member 90 having segmental channels 9I formed therein embraces the shaft and supports the rings 35. Insulating rings 92 are also supported upon the cylindrical member 90 and serve to space and insulate each ring 38 from its neighbors. The rings 92 and 35 are held clamped together between an end ring 93 which is secured to the shaft 31 by a pin 94 and an adjustable end ring 95 which is threaded upon a bushing 96, the bushing being fixed to the shaft 31 by a pin 91. Sockets 98 are provided in the periphery of the ring 95 to enable it to be turned upon'the bushing to clamp the rings 38 and 92 together as tightly as desired. An insulating sleeve or cylinder 99 surrounds the sleeve or cylinder formed by the rings 36 and 92, being carried by supports I which are mounted on the supporting frame member 89. The sleeve 99 is provided with a multiplicity of radial bores each of which'contains a stationary conductive block IOI which is connected through a terminal I02 with one of the conductors 35. Each block IOI urges inward a conductive compression spring I03 which bears 75 against a conductive plunger I04 to press a contact ball I05 into engagement with one of the rings 36. Each ring 36 is connected through a conductor 38 with a terminal I08 provided on the insulating ring 40. The conductors 38 are carried longitudinally of the'cylindrical sleeve 90 in the channels 9| thereof. i

Each terminal I03 is in the form of a screw which extends into a radial passage I01 formed in the ring 40. The inner end of each screw bears against a conductive plunger I08, and this plunger in turn acts through a conductive spring I09 to urge inward a conductive plunger IIO for maintaining a contact ball III in engagement with the periphery of the commutator ring 4|. The ring 40 is recessed to receive the commutator ring 4I and it is fixed upon a hub II2 which is made fast to the shaft 31 by a pin II3.

The commutator ring is composed of a central core portion I I4 which is fixedly supported from one of the brackets 88 through an insulating plate H5. The core portion H4, in turn, supports an insulating ring II8 which surrounds the core and which divides the space surrounding the core one of the rings 38, and thence through the associated conductor 38 and contact 39 with one of the character segments of the commutator ring 4|. 'It' will also be apparent that rotation of theshaft 31 will change the connections between the outer ring 40 and the inner ring M and thereby change the code for which the machine is set.

Provision is made for effecting this code changing rotation of the shaft 31 very expeditiously and efiiciently and in a simple manner. To this end the shaft 31 has fast upon it a ratchet wheel II9, which is adapted to be rotated step by step by means, oi a pawl I20. The pawl is pivoted upon one end of a lever I2I and is urged into en-.

gagement with the ratchet wheel bymeans of a spring I22 which is connected between the tail of the pawl and an ear I23 on the lever I2I. The lever I2I is pivoted at I24 and is normally held against a fixed stop I25 by means of a spring I28 which is connected to an arm of the lever and to a fixed frame member. The opposite arm of the lever I2I carries an armature I21 of an electromagnet I28. When the electromagnet I28 is energized, the armature is drawn down and there-1 by caused to operate the pawl to turn the ratchet vwheel I I9 a single tooth space. The ratchet teeth correspond in number and circumferential spacing to the contacts of the ring 40 so that each operation of the pawl sets up a new code.

It is important that the operator have some basis for determinng and controlling the code setting. Provision is accordingly made of a disc I29 fast upon the shaft 31 and provided with a single tooth I3I, the tooth being adapted to close an electric signal circuit in one code setting of the apparatus, which setting may be regarded as the zero position. The signal circuit referred to comprises conductor I4, a conductor I32, a signal light I33, a conductor I34, contacts I35 and I38, a conductor I31, conductors 59 and 60, contact I8, switch I1 and conductor I8.

As a convenient means for energizing the electromagnet I28 to operate the code setting mechanism to set up any predetermined code, provision is made of a dial I38 which is the same as the usual automatic telephone dial. The dial I38 is fast upon a shaft I39 and is provided with a series of finger openings I40. Numbers running in sequence appear on a stationary disc through the openings of the dial so that the dial may be rotated any desired number of steps by inserting the finger in the opening through which the desired number is seen and turning the dial until the rotation is arrested by engagement of the operators finger with a stationary stop MI. The dial, when operated, is returned by a spring (not shown) to the original position illustrated in Figure 1. The shaft I39 is connected through pawl and ratchet mechanism (not shown) to drive a disc I39 counterclockwise as the dial returns to starting position. The disc I39 is provided upon its periphery with a series of uniformly spaced knobs or pins I42. These pins are caused by rotation of the disc to travel successively over a resilient contact I43 to close a control circuit, the closing of which is efiective to cause another circuit which includes the winding of the electromagnet I28 to be closed.

The control circuit may be traced out from the terminal 21 to the terminal 51, the connections of these terminals with the positive and negative sides of the line having been previously described. Current flows from the terminal 21 through a resistance I44, a conductor I45 and a contact I46 through the resilient contact I43. The current passes thence through a contact I41, a switch member I48, a conductor I49, a solenoid I50, a conductor I5I and the conductor 51 to the terminal 51.

The solenoid I when energized pulls down a switch member I52 against a contact I53 and therebycloses the circuit of electromagnet I28. In this circuit the current flows from the terminal 21 through the switch member I52, the contact I53 and a conductor I54 to the winding I55 of electromagnet I28. The current passes thence through a conductor I56 to the conductor 51 and thence to the terminal 51. As soon as one of the pins or knobs I42 of the dial clears the contact I43 sufliciently to permit it to spring away from the contact I44, the circuit of solenoid I50 is broken, and this in turn permits the switch member I52 to move away from the contact I 53 and open the circuit of the electromagnet I28 so that the pawl I20 is returned to its original position under the influence of the spring I26. Each step that the dial is turned produces a single energization of the electromagnet I28 and a single feeding step of the ratchet wheel I I9. While successive operations of the dial are simply additive, any given code may be designated by any number whose digits add to the number of steps thatsuch code is removed from the zero setting. Thus a code which is set up by rotating the ratchet wheel fifteen steps from the zero position setting might be designated as code 96 or 18 or 654 or any other such combination of digits.

The circuit of the solenoid I50 which is controlled by the dial wheel has been described as including a contact I41 and a switch member I48. The purpose of the inclusion of this switch mechanism is to enable an authorized operator to leave the machine in such condition that there is no liability of the dial being operated by one ignorant of its purpose to change the code setting. The switch member I48 is held in engagement with the contact I41 by a cam member I51, which cam is mounted upon a key-controlled the space bar of the secondary machine.

shaft. The cam I51 is either of insulating material or is suitably insulated from the shaft. When the authorized operator leaves the machine. the shaft is turned to permit the contact between M1 to I48 to be broken and the key is taken out of the keyhole I58.

It is desirable when setting the machine to the zero position to be able to impart a series of single step movements to the ratchet wheel in rapid succession. For this purpose provision is made of a key switch I59 which is adapted to engage a contact I60, but which is normally held out of engagement with said contact by a spring I6I. The switch member I59 is connected to conductor I46 through a conductor I62 and the contact I60 is connected to contact I41 through a conductor I63. The closing of the switch I59 has the same effect as the closing of switch I43. The switch I59 is operated like a telegraph key, the operator watching after each closing of the switch for the indicator lamp I33 to light.

Provision may also be made for causing the code to be changed automatically each time the carriage of the primary machine is returned, if desired. To this end a switch I64 operable by the carriage return key I64 is connected in parallel with the switches I43 and I59 through conductors- I62 and I63 A switch I62 interposed in the conductor I62, may be set to open or closed position to render the switch I64 operative or inoperative as desired.

It will be observed that in the diagrammatic representation of Figure 3 a single contact of the ring 40 is designated both by a dash and the legend space and that upon the ring M a single contact segment is designated both by a dash and the legend space. With the particular setting illustrated in Figure 3 and from a mere inspection of said figure it might beinferred that operation either of the space bar or the dash key in the primary machine will produce the letter B in the secondary machine, and that operation of the letter B" in the primary machine will produce either a dash or an actuation of the space bar in the secondary machine. This is substantially true, alternative connections being provided to cause the space bar to produce 3" and B to produce a dash when coding, and to cause the dash to produce B and B to produce a-space when decoding. Thus when coding the dash key of the primary machine is rendered inoperative to influence the secondary machine, and the dash key of the secondary machine, but not the space bar, is rendered responsive to the letter 8 of the primary machine in the illustrative example. When decoding, the dash key of the primary machine is caused to operate the B key of the secondary machine, and the B key of the primary machine is caused to operate The letter B is merely used illustratively, it being the letter which happens to be involved when the code setting is that shown in Figure 3.

The space switch I9 of the primary machine is connected through a conductor I65 to a. terminal I66, and the dash switch I9 of the primary machine is connected through a conductor ductive arms I15, 8I and I16 which are insulated from one another. When the switch I14 is swun to the left (the position which it occupies when the apparatus is used for coding) the arm I15 connects the terminal I13 with a terminal I11, the arm 8| connects the terminal 82 with the conductor 80, and the arm I16 connects the terminal I66 with a terminal I18.

The operation will first be described on the I assumption that the switch I14 is in the left hand or coding position. In this position the terminal I68 which is connected with the dash switch I9 is a dead end so that the dash key of the primary machine is ineffective to produce any operation of the secondary machine. The terminal I66, which is connected to the space switch I9 of the primary machine is also connected to the ter-' minal I18. When the space switch of the primary machine is closed, current flows from the terminal 21 through conductors 28, 29, 8|, .the switch III and conductor I65 to terminal I66. It passes thence through switch arm I16, terminal I18, a conductor 32, a plug 33, a socket 84 and a conductor 35' to a ring 36*. From this point the current flows through a conductor 88 to a contact 39*" of the outer coding ring 48, thence to one of the segments 42 of the inner coding ring. The particular circuit being traced out is not shown in its entirety in Figure l, but it will be readily understood that the segment 42 is connected through a conductor 43, a plug 44, a socket 45, and a conductor 46 with one of the character operating solenoids of the secondary machine (for example, the solenoid of letter B") and that the current passes from said solenoid through conductor 5I, conductor 52, winding 53,

and conductors 54, 55, 56 and 51 to the terminal Still assuming that the switch I14 is in the coding position, it will now be assumed that the to the terminal I11, and thence across switch arm I15 to terminal I13. From the terminal I13 the current flows through conductor I12 to the dash solenoid 41 of the secondary machine. From the dash solenoid the current flows to the terminal 51* along the same path already described with reference to the other character solenoids of the secondary machine.

Thus, when coding, the operation of some character of the primary machine (illustratively the letter "13) produces an actuation of the dash key of the secondary machine. At this time the terminal I1I, which is connected to the space solenoid 85 of the secondary machine, is a dead end, and hence the letter "13, which is the only letter that could possibly directly actuate the space bar of the secondary machine with the code setting illustrated in Figure 8, is inoperative to influence said space bar.

The net result of the placing of the lever I14 in its left hand position is that the dash key of the primary machine cannot influence the secondary machine, the space bar of the primary machine produces the letter B in the secondary machine, and the letter B of the primary machine produces a dash in thesecondary machine.

When the switch I14 is swung to its right hand position, the apparatus is set for decoding, this being the only change required in order to change from coding to decoding. The switch arm I15 now bridges the gap between terminals HI and I11, and the switch arm I16 now bridges the gap between terminals I68 and I18. The terminal 82 becomes a dead end, so that the dash solenoid of the secondary machine is taken out of operation. The terminal I66 also becomes a dead end, so that the space switch I9 of the primary machine is taken out of operation. The dash switch I9 'oi' the primary machine is now connected through conductor I61, terminal I68, switch arm I16, and terminal I18 to the conductor 82. The remain ing elements of the circuit of which these elements form a part have been described in connection with the closing of the space switch of the primary machine with the apparatus set for coding. Thus, when decoding, the closing of the dash switch has the same eflect upon the secondary machine as the closing of the space switch has when coding, namely, to actuate the "3 key of the secondary machine when the setting is that of Figure 3. The closing of theB switch of the primary machine when decoding places the B" switch in communication with the contact 42 of the inner ring 4| and from this point the current flows through conductor 43' to terminal I11. From the latter point the current flows through switch arm I15, terminal "I and conductors I69 and 84 to the space solenoid 85 of the secondary machine, the remainder of the circuit being the same as that already described for the space solenoid 85. The net result of the swinging of the switch to the decoding position is that the space bar of the primary machine is rendered ineffective to influence the secondary machine, the dash key of the primary machine produces a letter (illustratively the letter "3") in the secondary machine, and the B key of the primary machine produces an actuation of the space bar of the secondary machine.

As has been stated, the apparatus is provided with means adapting it for operation from either an A. C. or a D. C. source of current, and the description up to this point has all related to the assumption that the connections are set for D. C. operation by inserting the plug 23 between the flexible contacts 24 and 25. When the apparatus is connected to an A. C. source of current supply, the plug 23 is withdrawn, and the flexible contacts 24 and 25 assume the positions indicated in Figure 1. The A. C. current from the line now flows through the conductors I4 and I5 to a contact I19, thence through a transformer winding I and conductors I8I, I82, I83 and 51 from which ,point the circuit to the line is completed through a path already described. The conductor I5 is also connected through a conductor I84 to form a part of the plate circuit of a vacuum tube rectifier I85. The details of the rectifier are of no importance in connection with the present invention, the function of the rectifier being simply to supply direct current to the operating instrumentalities of the apparatus other than the motors. Briefly, however, the filament circuit I86 of the rectifier tube is inductively supplied with current from the transformer primary I811. The plate circuit comprises the conductor I 84, the filament circuit of the rectifier, a conductor I81 which is center tapped to transformer secondary winding I88, a conductor I89, a contact I88, the flexible contact 24, and the conductor 26 to the terminal 21. The completion of the circuit from the terminal 21 to the conductor I8 has structures.

been traced out through the various channels which it may follow in the description for direct current operation.

Suitable auxiliary means are provided at various points in the circuit comprising either condensers or condensers and resistances appropriately connected for preventing sparking and other purposes, but since these elements are mere details having only to do with the eflicient carrying out of the purposes already described, no detailed description of them is deemed necessary.

In certain of the appended claims the term space bar is used for brevity. Any suitable space-producing key or keyboard member is intended to be comprehended in this term. Similarly, certain of the claims refer for brevity and clearness to the dashkey of the primary machine and to the dash type of the secondary machine. This term is intended to comprehend any little used character or any character which would not necessarily have to form a significant part of an uncoded message.

While I have illustrated and described in detail certain preferred forms of my invention, it is to be understood that changes may be made therein and the invention embodied in other I do not, therefore, desire to limit myself to the specific constructions illustrated, but intend to cover my, invention broadly in whatever form its principle may be utilized.

I claim:

1. In a coding and decoding machine, in combination, a manually operable primary machine, a secondary machine operable from the first, coding mechanism interposed between and interconnecting the machines, and means under the control of the operator for causing automatically measured adjustments of selected extent to be imparted instantaneously to the coding mechanism, as desired, to efiect an arbitrary change of the code setting.

2. In a coding and decoding machine, in combination, a manually operable primary machine, a secondary machine operable from the first, coding mechanism interposed between and interconnecting the machines, means under the control of the operator for instantaneously adjusting the coding mechanism as desired to effect an arbitrary change of the-code setting, and means for rendering the code changing means inoperative, including a key-controlled lock.

3. In a coding and decoding machine, in combination, a manually operable primary machine, a secondary machine operable from the first, coding mechanism interposed between and interconnecting the machines, means under the control of the operator for instantaneously adjusting the coding mechanism as desired to efiect an arbitrary change of the code setting, and

means for rendering the code changing means inoperative, including a normally open switch, means for closing said switch, and key-controlled means for rendering said switch closing means inoperative. 1

4. In a coding and decoding machine, in combination, a manually operable primary machine,

and a series of circuit closing members driven by the dial for closing the circuit repeatedly upon a single actuation of the dial to energize the electromagnetic code changing means a number of times corresponding to the extent of the dial operation.

5. In a coding and decoding apparatus, in combination, a primary manually operable machine including a keyboard and a space bar, a secondary machine responsive to the operation of the first and including character types and space bar mechanism, transposing means interconnecting the machines for causing operation of either a character key or the space bar of the primary machine to effect operation of a character type of the secondary machine, means for automatically operating the space bar mechanism of the secondary machine after a predetermined number of keyboard operations of the primary machine, means settable to render said automatic spacing means operative or inoperative as desired, and means settable to render the spacing mechanism of the secondary machine nonresponsive to individual character key operation of the primary machine when the automatic spacing means is effective.

6. In a coding and decoding apparatus, in combination, a primary manually operable machine including a keyboard and a space bar, a secondary machine responsive to the operation of the first and including character types and space bar mechanism, transposing means interconnecting the machines for causing operation of either a character key or the space bar of the primary machine to efiect operation of a character type of the secondary machine, means for automatically operating the space bar mechanism of the secondary machine after a predetermined number of keyboard operations of the primary machine, means settable to render said automatic spacing means operative or inoperative as desired, and means automatically effective to render the .space bar mechanism of the secondary machine non-responsive to individual character key operation of the primary machine when the automatic spacing means is efiective.

V '7. In a coding and decoding apparatus, in combination, a primary manually operable machine including a keyboard and a space bar, a secondary machine responsive to the operation of the first and including character types and spacing mechanism, transposing means interconnecting the machines for causing operation of either a character key or the space bar of the primary machine to eiiect operation of a character type of the secondary machine, means for automatically operating the spacing mechanism of the secondary machine after a predetermined number of keyboard operations of the primary machine, and means settable to one position simultaneously to render the automatic spacing means inoperative and to break the operating connection from the space bar of the primary machine to the secondary machine, and settable to another position simultaneously to render the automatic spacing means operative and to reestablish the operating connection from the space bar of the primary machine to the secondary machine.

8. In a coding and decoding apparatus, in combination, a primary manually operable machine including a keyboard and a space bar, a secondary machine responsive to the operation of the first and including character types and space bar mechanism, transposing means interconnecting the machines for causing operation of either a character key or the space bar of the primary machine to effect operation of a character type of the secondary machine, means for automatically operating the space bar mechanism of the secondary machine after a predetermined number of keyboard operations of the primary machine, and means settable to one position to simultaneously render the automatic spacing means inoperative and the space bar mechanism of the secondary machine directly responsive to keyboard operation of the primary machine, and to break the operating connection from the space bar of the primary machine to the secondary machine, and settable to another position simultaneously to render the automatic spacing means operative and the space bar mechanism of the secondary machine non-responsive to direct character key operation of the primary machine, and to re-establish the operating connection from the space bar of the primary machine to the secondary machine.

9. In a coding and decoding apparatus, in combination, a primary manually operable machine having a keyboard including character keys and a space bar, a secondary machine including character keys and spacing mechanism, transposing means interconnecting the machines to operate the secondary machine from the primary machine to cause the writing of a message on the primary machine, including all of the characters and spaces thereof, to produce in the secondary machine a code messagein which each of the characters and spaces of the uncoded message is replaced by a character, said means including mechanism for automatically introducing spaces to divide the code characters into equal groups, and, means instantaneously settable to change the mode of operation of the apparatus for decoding, to cause the writing of the coded message on the primary machine, including all of the characters and spaces thereof, to produce in the secondary machine an exact reproduction of the uncoded message with all of the original characters and spaces correctly included, and the automatically introduced spaces eliminated.

10. In a coding and decoding machine, in combination, a primary machine having a keyboard including character keys and a space bar, a secondary machine including character types and a spacer, coding means connecting the machines for in general causing any keyboard operation of the primary machine to effect the printing of a substitute character in the secondary machine, but including means -for making the space bar and the dash key of the primary machine, al: ternatively effective for coding and decoding, respectively, to produce the same character operation of the secondary machine.

11. In a coding and decoding machine, in combination, a primary machine having a keyboard including character keys and a space bar, a secondary machine including character types and a spacer, coding means connecting the machines for in general causing any keyboard operation of the primary machine to efiect the printingof a substitute character in the secondary machine, but including means for making the dash type and the spacer of the secondary machine alternatively responsive, for coding and decoding, respectively, to the same character key operation of the primary keyboard.

12. In a coding and decoding machine, in com: bination, a primary machine having a keyboard including character keys and a space bar, a secondary machine having operating instrumentaliboard operates a particular substitute operating.

instrumentality of the secondary machine, and operation of the primary key corresponding to the substitute operating instrumentality operates an operating instrumentality of the secondary machine corresponding to the key originally operated, but in which provision is made of adjustable means for alternatively producing the same code character by the space bar when coding and by the dash key when decoding, and for alternatively producing dashes by operation of a particular key when coding and spaces by operation of the same key when decoding.

13.. In a coding and decoding machine, in combination, a manually operable primary machine, a secondary machine operable from the first, coding mechanism interposed between and interconbythe dial for closing the circuit repeatedly upon a single actuation of the dial to energize the electromagnetic code changing means a number of times corresponding to the extent of the dial operation, means for indicating a datum or zero code setting, and a separate manually operable circuit closing switch for operating the electromagnetic code changing means step by step to the zero setting.

14. In a coding and decoding machine, in combination, a manually operable primary machine, a secondary machine operable from the first coding mechanism interposed between and interconnecting the machines, meansunder the control of the operator for instantaneously and automatically adjusting the coding mechanism to a selected extent as desired to efiecta selected arbitrary change of the code settin and means responsive to a key operation of the primary machine to change the code-setting automatically from time to time.

15. In a coding and decoding machine, in combination, a manually operable primary machine,

a secondary machine operable from the first, coding mechanism interposed between and interconnecting the machines, means under the control of ,the operator for instantaneously adjusting the coding mechanism as desired to eiTect an arbitrary change of .the code setting, and means responsive to the carriage return operation of the primary machine to change the code setting automatically.

16. In a coding and decoding machine, in combination, a manually operable primary machine,

a secondary machine operable from the first, coding mechanism interposed between and interconnecting the machines, means under the control of the operator for instantaneously adjusting the coding mechanism as desired to eflfect an arbitrary 'changeof the code setting, means responsive to the carriage return operation of the'primary machine to change the code setting automatically,

and means-for rendering said automatic code.

changing means operative or inoperative as desired.

1'7. In a coding or decoding apparatus, in com bination, a primary machine having a keyboard, a secondary machine having operating instrumentalities, and coding means connecting the machines to control operation of the secondary machine from the primary machine comprising a series of electrical circuits each adapted to be selectively closed for a predetermined time by keyboard operation of the primary machine, each circuit including a power operated switch under the control of a keyboard member of the primary machine and mechanical power means included in the primary machine for mechanically clos-- ing each switch in a positive and uniform manner and for a predetermined period in response to keyboard operation.

18. In a coding and decoding apparatus in combination, a power operated primary machine having a keyboard and writing instrumentalities, a secondary machine having writing instrumentalities, and coding means connecting the machines to control the operation of the secondary machine from the primary machine comprising a series of electric circuits each including a switch, the primary machine including a series of power operated members each individual to one of the keyboard members and adapted to be mechanically tripped by the latter for operating one of the writing instrumentalities of the primary machine and effective when tripped to close one of the switches in a positive and'uniform manner and for a predetermined period.

19. In a coding and decoding machine, in combination, a manually operable primary machine, a secondary machine operable from the first, coding mechanism interposed between and interconnecting the machines, and means responsive to mechanism controlled in accordance with the arbitrary and irregular arrangement of grouping of words of a message to efiect automatically the the last mentioned means comprises the carriage return mechanism.

21. A coding and decoding machine comprising a manually operable primary machine, a secondary machine operable from the first, coding means comprising a single movable circuit changing device interposed between and interconnecting the machines, and an electrical control circuit under control of the primary machine to control the positioning of the said coding means at irregular and arbitrary intervals.

WALTER S. LEMMON. 

